Finding the Fourth Proportional to 78.78, 108.61 and 67.84

Step by Step Solution

1. Step 1: Write the proportion equation
   78.78 : 108.61 = 67.84 : x
2. Step 2: Convert to fraction form
   78.78/108.61 = 67.84/x
3. Step 3: Cross multiply
   78.78x = 108.61 × 67.84
4. Step 4: Simplify right side
   78.78x = 7,368.10
5. Step 5: Solve for x
   x = 7,368.10/78.78
6. Step 6: Final answer
   x = 93.53